Computer devices are widely used for entertainment activities such as playing games. Currently, popular gaming computer devices include game consoles connected to a home television set, such as the Nintendo® 64 from Nintendo Corp., the Playstation® from Sony Corp., and the Dreamcast™ from Sega Corp. Gaming computer devices also include personal computers, such as Windows PCs, Macintosh computers, and others. Also, portable computer devices are often used for entertainment purposes, such as Game Boy® from Nintendo, personal digital assistants such as PalmPilot® from Palm Computing, and laptop computers.
Users of these computer devices typically interact with a game or other application program using an interface device connected to the host computer (e.g. game console). Such interface devices may include joysticks, gamepads, mice, trackballs, styluses, steering wheels, or other devices. A user moves a user manipulatable object (manipulandum), such as a joystick, wheel, mouse, button, dial, or other object, which is sensed by the host computer and used to manipulate a graphical environment displayed by the host computer. Recently, haptic feedback in interface devices has become available as well, where the host computer and/or a microprocessor on the interface device controls one or more motors to output forces to the user. These forces are correlated with events or objects in the graphical environment to further immerse the user in the gaming experience or interface task. Herein, the term “haptic feedback” is intended to include both tactile (or vibrotactile) feedback (forces transmitted to user skin surfaces) and kinesthetic feedback (forces provided in degree(s) of freedom of motion of the manipulandum).
In the game console market, products are typically produced in high volume and low cost. Therefore, haptic feedback interface devices have been typically limited to simpler embodiments that provide more limited forms of haptic feedback. Existing force feedback “gamepad” controllers (or add-on hardware for gamepad controllers) that are used to interface with games running on game consoles include the Dual Shock™ from Sony Corp., the Rumble Pak™ from Nintendo Corp., and the Jump Pack from Sega Corp, as well as other types of handheld controllers such as the MadCatz Dual Force Racing Wheel. These devices are inertial tactile feedback controllers which employ one or more motors to shake the housing of the controller and thus provide output forces such as vibrations to the user which are correlated to game events and interactions. Typically, an eccentric rotating mass (ERM) motor, i.e., pager motor, is used to generate vibration on the controller and thus to the user. The motor is rigidly coupled to the controller housing and provides a mass on a rotating shaft offset from the axis of rotation, so that when the shaft is rotated, the inertial forces from the moving mass rock the motor and the gamepad housing back and forth.
One problem with existing tactile controllers is that they are limited in the magnitude of forces output to the user. Devices driving a motor and mass in only one rotational direction tend to provide greater amplitude forces in an inertial tactile device, but the forces are not as crisp, precise, or controllable as forces output by a harmonically (bidirectional) driven motor and mass. The drawback of the harmonically-driven mass, or low power tactile devices, is that the forces are often not strong enough to be compelling to the user, especially in applications such as games or virtual reality.